Salmonellosis is one of the most prevalent foodborne illnesses. The outbreak of this disease is often associated with eggs. In this study, the prevalence and characteristics of Salmonella was surveyed in layer farms in Korea. In addition, the risk factors affecting the prevalence of Salmonella in these farms were also assessed. Of the 32 farms and 67 flocks examined, 19 farms (59.3%) and 34 flocks (50.7%) were observed to be positive for Salmonella contamination. Salmonella was detected in the surrounding environment such as feces (41.8%), dust (40.3%), egg shells (17.2%), as well as the internal egg contents (5.2%). The incidence of Salmonella positives were tended to increase when the flock size is larger (P = 0.021). Differences in the provinces also affected Salmonella prevalence (P < 0.001). The most frequently observed Salmonella serovars in the flocks were Salmonella Bareilly (41.2%), Salmonella Mbandaka (32.4%), and Salmonella Rissen (17.6%). Twenty of the flocks revealed multi-serovar contamination, with the isolation of 2 to 4 serovars. Antimicrobial susceptibility testing revealed that 93 out of 101 isolates were susceptible to the 17 tested antimicrobial agents. The remaining isolates displayed resistance to ampicillin (4.0%), nalidixic acid (3.0%), tetracycline (1.0%), cephalothin (1.0%), and gentamicin (1.0%). As human salmonellosis has been repeatedly correlated to the consumption of poultry products worldwide, continuous studies are required to effectively minimize the Salmonella contamination in layer farms and egg products.

Edible offal meats have recently received significant attention worldwide. However, studies evaluating the microbial quality of diverse edible offal and specifically investigating contamination by pathogens that cause foodborne illnesses are rare. Our study was conducted to investigate the microbiological quality of six kinds of edible offal produced from 11 pigs and 8 cattle slaughterhouses in the Republic of Korea and the prevalence of pathogenic microorganisms such as Salmonella, Clostridium perfringens, Staphylococcus aureus, and Escherichia coli O157:H7 in these products. The values for aerobic plate counts, coliform counts, and E. coli counts in red offal were 1.00 to 6.70, 0 (below 10 CFU) to 4.78, and 0 to 4.00 log CFU/g, respectively. For green offal, the values were 3.00 to 7.00, 1.48 to 6.30, and 0 to 6.00 log CFU/g, respectively. The most frequently detected foodborne pathogen was Salmonella (23.8% prevalence in pig offal and 7.1% prevalence in cattle offal), followed by C. perfringens (11.1 and 7.1%, respectively) and S. aureus (12.7 and 2.4%, respectively). None of the offal samples tested positive for E. coli O157:H7. Considering the microbial quality of offal from Korean slaughterhouses and the prevalence of foodborne pathogens in this material, more refined hygienic standards such as a hazard analysis critical control point system for processing, packing, and transporting edible offal are necessary for preventing further contamination.

Salmonella enterica serovar Bareilly (S. Bareilly) has been among the top 20 most frequently isolated serovars in the United States and has been observed recently in layer flocks in Korea. Between 2013 and 2014, 45 S. Bareilly isolates were obtained from five commercial layer farms and nine retail markets in Korea. Among the 45 isolates, four pulsed-field gel electrophoresis patterns were observed, with pattern B being the predominant and comprising 67% of the 45 isolates. The most common antimicrobial resistance was streptomycin (24.4%) and cephalothin (6.7%). This is the first report describing epidemiological characteristics of S. Bareilly, including geographical variation, in Korea.